The main thing intended by shunning what is not one’s concern is protecting the tongue from idle talk. Allâh the Exalted says,وَلَقَدْ خَلَقْنَا الْإِنْسَانَ وَنَعْلَمُ مَا تُوَسْوِسُ بِهِ نَفْسُهُ وَنَحْنُ أَقْرَبُ إِلَيْهِ مِنْ حَبْلِ الْوَرِيدِ. إِذْ يَتَلَقَّى الْمُتَلَقِّيَانِ عَنِ الْيَمِينِ وَعَنِ الشِّمَالِ قَعِيدٌ. مَا يَلْفِظُ مِنْ قَوْلٍ إِلَّا لَدَيْهِ رَقِيبٌ عَتِيدٌ.
which means (And indeed We have created man, and We know what his own self whispers to him. And We are nearer to him than his jugular vein [by our knowledge]. [Remember] that the two receivers [recording angels] receive [each human being], one sitting on the right and one on the left [to note his or her actions]. Not a word does he [or she] utter but there is a watcher by him, ready [to record it]) (Qâf; 50: 16-18)
‘Umar bin ‘Abdl-‘Azîz (may Allâh be Merciful with him) said, "Whoever reckoned his words as part of his actions would speak very little. This is true, for many people do not consider that their speech is from their actions. Thus, they speak recklessly, not paying attention to their words. This was unknown to Mu’âdh bin Jabal until he asked the Prophet (peace be upon him) about it, saying, “Will we be held accountable for what we say?” So he answered, “O Mu’âdh, may your mother be bereaved of you. Is there anything that topples people on their faces or their noses into Hell-fire other than what their tongues reap?”[1] And Allâh thus negated good from much of what men speak secretly about. For Allâh says,لَا خَيْرَ فِي كَثِيرٍ مِنْ نَجْوَاهُمْ إِلَّا مَنْ أَمَرَ بِصَدَقَةٍ أَوْ مَعْرُوفٍ أَوْ إِصْلَاحٍ بَيْنَ النَّاسِ
which means, (There is no good in most of their secret talks save (in) him who orders charity and righteousness, or conciliation between mankind. As for him who does this, seeking the good pleasure of Allâh, We shall give him a great reward”) (An-Nisâ’; 4:114)
It is narrated on the authority of Anas that he said, “A man from among the companions of the Prophet (peace be upon him) died; so a man asked, ‘Rejoice with the good news of Paradise!’ So the Prophet (peace be upon him) answered, ‘You won’t be able to know, for it might be that he spoke about what didn’t concern him or was stingy with what would not make him rich.”[2] The meaning of this hadîth was narrated in different forms from the Prophet (peace be upon him); and in one of them it says that the man was killed as a martyr.